Since we don't reset the proto_csum_blank flag in the skb, the

checksum calculation gets done twice, which is not twice as good as
once.

With this patch, TCP/UDP checksum errors from dom0 are fixed, and
domUs can use TCP/UDP without turning off TX checksum offload.  Normal
non-VLAN bridged configs still work fine, tested with xm-test.

Signed-off-by: Jim Dykman <dykman@us.ibm.com>

diff --git a/linux-2.6-xen-sparse/net/core/dev.c b/linux-2.6-xen-sparse/net/core/dev.c
index 7a98ceb6585454c3e8755dd462568f3cc10cfd0d..e526fccc2f9d326c10a096f81c9e4509940e55b2 100644 (file)
--- a/linux-2.6-xen-sparse/net/core/dev.c
+++ b/linux-2.6-xen-sparse/net/core/dev.c
@@ -1294,6 +1294,7 @@ int dev_queue_xmit(struct sk_buff *skb)
                if ((skb->h.raw + skb->csum + 2) > skb->tail)
                        goto out_kfree_skb;
                skb->ip_summed = CHECKSUM_HW;
+               skb->proto_csum_blank = 0;
        }
 #endif